In a large nonstick skillet, heat the oil until hot but not smoking over medium heat. Add the onion and cook, stirring frequently, until softened about 5 minutes. Stir in the carrot, celery, and 1/3 cup of water and cook until the vegetables are tender and the liquid has evaporated about 5 minutes longer. Stir in the ground beef and cook until no longer pink about 4 minutes. Add the wine and cook until the liquid has evaporated about 5 minutes. Stir in the tomato paste, 2/3 cup of milk, the salt, pepper and oregano, reduce to a simmer and cook, stirring frequently, until the milk has been absorbed. Continue to cook until the sauce is thick and creamy, gradually adding the remaining 1 cup milk until all has been absorbed about 20 minutes longer. Meanwhile, cook the pasta in a large pot of boiling water until just tender. Drain well. Transfer the sauce to a large bowl. Add the pasta, parsely, if desired and the Parmesan and toss to combine. Spoon the Penne Bolognese into 4 serving bowls. Suggested accompaniments: Shredded Belgian endive with cooked frown artichoke hearts tossed with a nonfat Italian dressing.